This circuit was found in Motorola documentation from 1968. SCRs can be modern equivalents and the maximum load is 5 A at 40 V.
This circuit is suitable for low impedance m icrophones. Gain is given by the 2M2 resistor. This...
This sensitive circuit was found in old documentation. The SCR can be any of the 106 series and...
This preamp with several inputs using germanium transistors from the time was found in Japanese...